1. Field of the Invention
The present invention relates to an oral hygiene system comprising an oxygen-containing gas-driven, otherwise propellantless foam dispenser and a foamable oral hygiene formulation. More particularly, it relates to such system which is a personal self administrable oral hygiene system driven by air and producing aerated foams. The invention also relates to such an oral hygiene system driven by a high molecular oxygen content gas to be administered by mouthcare professionals.
2. The Prior Art
Formulations are known, many commercially available over-the-counter (OTC), for improving oral hygiene. Included are self-administrable OTC mouthwashes, rinses, gargles and dentrifices, as well as topical treatments to be administered by a trained professional. In general, the mouthwashes, rinses, gargles, and dentrifices for self-treatment are aqueous or aqueous alcoholic liquid solutions, pastes or gels incorporating one or more orally-acceptable antimicrobial, anti-plaque and/or anticariogenic agents, often in association with such auxiliary components as demulcents, mouth-wound cleansing and healing agents, astringents, analgesics, solution thickeners, sweeteners, flavorants, colorants and surfactants.
Representative liquid mouthcare formulations are disclosed in Talwar et al U.S. Pat. No. 4,945,087 relating to thymol-based antimicrobial mouthwashes and rinses; Goldemberg et al., U.S. Pat. No. 4,666,708 directed to plaque-loosening and removing alkaline dental rinses comprising sodium benzoate, a detergent builder and a surfactant; Douglas, U.S. Pat. No. 5,104,644 disclosing hydrogen peroxide-based anti-plaque and antibacterial mouthwashes; and Shah, U.S. Pat. No. 4,325,939 disclosing plaque-loosening rinses comprising zinc compositions.
The OTC liquid mouthwashes and rinses appear designed to provide effective daily oral care treatment with typical doses of about 0.5 to 1 fluid ounce (about 14 to 28 grams). The dose is to be intimately contacted with all surfaces of the oral cavity, as by swirling, for about 30 to 60 seconds; then expectorated substantially completely, without swallowing.
Many of the formulations and the method of self-treatment are not entirely satisfactory. Under the recommended conditions, much of the mouthcare material is considered wasted inasmuch as it is only that proportion of the dose that is at the outer surface of the body of liquid that is in direct interfacial contact at any one time with the target surfaces of the oral cavity. Thus, at the relatively short treatment times involved, a substantial proportion of the "actives", i.e., active ingredients, of the liquid dose remains in its interior out of contact with the target surfaces, hence unavailable for effective treatment, especially when the user fails to vigorously swish the material within the buccal cavity.
Another problem associated with the presence of excess amounts of liquid formulation in the mouth at any one time is that many of the ingredients are or believed to be harmful if ingested, e.g. fluorides, or maintained in contact with buccal tissues at high concentrations, e.g. alcohol, so that it is desirable to minimize the total amounts of such substances in the mouth during the treatment.
In view of the excess ingredient problem associated with fluoridating pastes and gels, Pellico, U.S. Pat. No. 4,770,634 discloses a fluoridating method, for use by dental professionals, which comprises treating teeth with foamed fluoride compositions. The method involves dispensing a foamable aqueous acid solution of a dental fluoride, a selected foaming agent and a foam wall thickener from a pressurized aerosol container by means of propane or isobutane as propellant. The formulation and the method of dispensing it are designed to provide dense, stable, non-flowable foams within the trough of a dental tray, which is superimposed about, and in engagement with the teeth to be treated for periods of 1 to 4 minutes, thereby to effect fluoride uptake by the dental enamel. Pellico teaches the benefit of limiting the total quantity of fluoride in the mouth during the treatment during the treatment period to safer levels than those provided by pastes and gels.
The Pellico system suffers in that it requires the aid of a third party and presents the hazard of handling a flammable gas maintained under super-atmospheric pressure. Thus, it is not entirely suitable for home use as a personal, self-administrable oral hygiene system.
Also known, in art unrelated to oral hygiene, are-driven, so-called propellantless devices for producing and dispensing foam that rely on the use of a reversibly compressible and decompressible container housing a foamable liquid and air normally at rest at substantially atmospheric pressure. Foam is produced by compressing, e.g. squeezing, the container, whereby the internal air pressure is increased sufficiently to force both liquid and air into a foam-producing mixing chamber and subsequently resulting in the expression of foam from the device. Allowing the container to decompress allows outside air to be drawn into the container through an appropriate valve and restore the system to its normal at rest, substantially atmospheric pressure, condition. Representative of such propellantless devices are those described in the following U.S. Patents: Wright U.S. Pat. No. 3,709,437; Kazuo U.S. Pat. Nos. 4,274,594 and 4,432,496; Grogan et al. U.S. Pat. No. 4,615,467; Ford et al. U.S. Pat. No. 4,640,440; Rosenberg U.S. Pat. No. 4,836,422; and Tobler U.S. Pat. No. 5,048,750. Collectively, these patents disclose that foam dispensers are useful for dispensing detergents, polishers, waxes, cosmetics, toiletries and foodstuffs. None disclose or suggest dispensing products relating to oral hygiene.
Poll et al, U.S. Pat. No. 5,369,131, issued Nov. 29, 1994, on a U.S. application filed May 20, 1993, discloses and claims liquid pharmaceutical compositions that are propellant free and mechanically foamable comprising at least one pharmaceutically active ingredient, a surfactant, a water-containing solvent, at least one of a mucoadhesive polymer and a thermosetting polymer. The foams may be used for oral, cutaneous or intravaginal administration. The surfactants may be ionic or preferably nonionic. Oral foams are intended to be ingested. Oral hygiene formulations are not disclosed.
A need exists for an improved system of dispensing foamed oral hygiene products simply and directly, efficiently and safely, to the oral cavity target areas, particularly such system suitable for self-treatment.
A need also exists for improved oral hygiene products that are foamable and dispensable by conventional gas-driven dispensers that avoid the use of environmentally objectionable gaseous chlorofluorocarbons (CFCs) and flammable hydrocarbons.